1、Designation: D4611 16Standard Test Method forSpecific Heat of Rock and Soil1This standard is issued under the fixed designation D4611; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenthes
2、es indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determination of instanta-neous and mean values of the specific heat of rock and soil.1.2 This test method employs the classi
3、cal method ofmixtures, which involve procedures and an apparatus that aresimpler than those generally used in scientific calorimetry, butwith an accuracy that is adequate for most rocks and soils.While this test method was developed for testing rock and soil,it can be adapted to measure the specific
4、 heat of othermaterials.1.3 The testing procedure provides an instantaneous specificheat over temperatures ranging from 25 to 300C or a meanspecific heat in that temperature range.1.4 The test procedure is limited to dry specimens of soiland rock.1.5 UnitsThe values stated in SI units are to be rega
5、rdedas the standard. No other units of measurements are included inthis standard.1.6 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.6.1 The procedure used to specify how data are collected/recorded or calculated in
6、 this standard are regarded as theindustry standard. In addition, they are representative of thesignificant digits that generally should be retained. The proce-dures used do not consider material variation, purpose forobtaining the data, special purpose studies, or any consider-ations for the users
7、objectives; and it is common practice toincrease or reduce significant digits of reported data to becommensurate with these considerations. It is beyond the scopeof this standard to consider significant digits used in analyticalmethods for engineering design1.7 This standard does not purport to addr
8、ess all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D618 Practice
9、for Conditioning Plastics for TestingD653 Terminology Relating to Soil, Rock, and ContainedFluidsD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD6026 Practice for Using Significant Digits in Geote
10、chnicalDataE122 Practice for Calculating Sample Size to Estimate, WithSpecified Precision, the Average for a Characteristic of aLot or ProcessE230 Specification and Temperature-Electromotive Force(EMF) Tables for Standardized Thermocouples3. Terminology3.1 For definitions of common technical terms u
11、sed in thisstandard, refer to Terminology D653.3.2 Definitions:3.2.1 instantaneous specific heatthe rate of change ofsample enthalpy, h, per unit mass with respect to temperature,T, at constant pressure, p, (J/kgK).3.2.2 mean specific heatthe quantity of heat required tochange the temperature of a u
12、nit mass of a substance onedegree, measured as the average quantity over the temperaturerange specified (J/kgK).3.2.3 thermal capacitythe amount of heat necessary tochange the temperature of the body one degree, equal to theproduct of the mass of the body and its specific heat (J/K).3.2.4 thermal di
13、ffusivitythe ratio of thermal conductivityof a substance to the product of its density and specific heat(m2/s).3.3 Symbols:3.3.1 Henthalpy change (J/kg).1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.12 on Rock Me
14、chanics.Current edition approved May 1, 2016. Published May 2016. Originallyapproved in 1986. Last previous edition approved in 2008 as D4611 08. DOI:10.1520/D4611-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual
15、Book of ASTMStandardsvolume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.3.2 (H)calenth
16、alpy change of the calorimeter (J/kg).3.3.3 mmass (kg).3.3.4 mcalmass of calorimeter (kg).3.3.5 mcapmass of capsule (kg).3.3.6 mspecmass of the specimen (kg).3.3.7 mcpthermal capacity (J/K).3.3.8 Tmfinal temperature of the mixture (K).3.3.9 Tctemperature of the calorimeter immediately priorto drop (
17、K).3.3.10 Thtemperature of capsule and specimen in theheater prior to drop (K).3.3.11 Ttemperature difference (K).3.3.12 (T)caltemperature change of the calorimeter (K).3.3.13 (cp)specmean specific heat of the specimen (J/kgK).3.3.14 (cp)specinstantaneous specific heat of the specimen(J/kgK).3.3.15
18、(cp)calinstantaneous specific heat of the calorimeter(J/kgK).3.3.16 (cp)capinstantaneous specific heat of the capsule(J/kgK).4. Summary of Test Method4.1 The method of mixtures consists essentially of adding aknown mass of material at a known temperature to a knownmass of calorimetric fluid at a kno
19、wn lower temperature anddetermining the equilibrium temperature that results. The heatabsorbed by the fluid and containing vessel can be calculatedfrom calibrations and this value equated to the expression forthe heat given up by the hot material. From this equation, theunknown specific heat can be
20、calculated. If only one drop froma single temperature is performed, then only the mean specificheat can be calculated. If several drops are performed, theinstantaneous specific heat can be calculated.5. Significance and Use5.1 Specific heat is a basic thermodynamic property of allsubstances. The val
21、ue of specific heat depends upon chemicalor mineralogical composition and temperature. The rate oftemperature diffusion through a material, thermal diffusivity, isa function of specific heat; therefore, specific heat is anessential property of rock and soil when these materials areused under conditi
22、ons of unsteady or transient heat flow.NOTE 1The quality of the result produced by this standard isdependent on the competence of the personnel performing it, and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D3740 are generally considered capable of
23、 competentand objective testing/sampling/inspection/etctesting. Users of this stan-dard are cautioned that compliance with Practice D3740 does not in itselfassure reliable results. Reliable results depend on many factors; PracticeD3740 provides a means of evaluating some of those factors.6. Apparatu
24、s6.1 CalorimeterThe calorimeter shall be an unlaggedvacuum flask. The capacity of the vacuum flask shall be suchas to yielda1to5Ktemperature rise of the receiver fluid withaverage sample size used during testing (Note 2). The flaskshall have an insulated cover or stopper.NOTE 2Typical volumes of vac
25、uum flasks used for this type ofmeasurement are approximately 500 to 750 mL for rock or soil samples of50 g in thin-wall copper or stainless steel capsules.6.2 Magnetic stirrer equipped with a speed regulating de-vice.6.3 Calorimeter Temperature-Sensing DeviceAtemperature-sensing device with a minim
26、um resolution of0.0025 K and an accuracy of 60.5 % and capable of measuringa change in temperature of at least 5 K shall be used.NOTE 3A suitable temperature sensor is a multijunction thermopiletypically referenced to an ice bath.6.4 Calorimeter FluidThe calorimeter fluid shall be a highspecific hea
27、t fluid, stable to 520 to 570 K and having a lowvapor pressure.NOTE 4Silicone based fluids have been found to meet this require-ment.6.5 HeaterThe heater shall be designed to provide auniform heating zone. A maximum variation of 61%ofthemean heater temperature along the heater length correspondingto
28、 the sample is permitted.NOTE 5Typically, open-end radiation type heaters similar to thecylindrical device shown in Fig. 1 are used. Such heaters are usuallyheated by electricity; however, other means of heating are acceptable aslong as the requirements for the heater can be met. The relativedimensi
29、ons of the heater and capsule shall be such that the specimen willbe heated to a uniform and constant temperature as required. The heatershould be provided with an insulated removable cover designed to permitpassage of sample capsule temperature sensing devices and suspensionwire. The bottom should
30、be closed with a removable insulated cover topermit free dropping of the capsule. Typically, the heater assembly ismounted so it can be swung quickly into place over the calorimeterimmediately prior to drop and swung away after the sample has beendropped.FIG. 1 Specific Ileal CalorimeterD4611 1626.6
31、 CapsuleThe capsule shall be of the hermeticallysealed type. The capsule heat capacity shall be minimized andin no instance shall be greater than the heat capacity of thesample. The capsule shall be made of high conductivitymaterial. Typically, capsules are thin wall copper or stainlesssteel contain
32、ers.6.7 Specimen Temperature Readout DeviceA convenientmethod of measuring the temperature of the sample in theheater unit shall be provided. It is desirable to measure thesample temperature inside the capsule; however, measuring ofthe outside of the capsule is permitted. Typically, a thermo-couple
33、calibrated to the special limits of error specified in EMFTables E230 is used for sample temperature readout. Thetemperature shall be measured to 61 % of the test temperature.6.8 Test RoomThe room temperature in which the tests areconducted shall be maintained at 296 6 2K.6.9 Calibration SpecimensA
34、minimum of three traceablecalibration specimens are required.NOTE 6Commonly used calibration specimens are sapphire or plati-num.7. Test Specimen7.1 FormIn order to increase the accuracy of this testmethod, the specimen mass shall be maximized for a givencapsule volume. This usually means, for dense
35、 rocks, that thespecimen shall be machined to fit the capsule tightly. However,crushed rocks in powder form or soils can be tested with adecrease in accuracy due to the lower contribution of thesample to the total measured heat capacity of the specimen/capsule combination. Porous rocks are usually t
36、ested in powderform.7.2 Statistical RequirementsThe number of samples andspecimens tested shall be sufficient to provide an adequatestatistical basis for evaluation of the results. Rock types that arehighly variable will require more tests than relatively uniformrocks in order to evaluate the result
37、s with equal uncertainty.7.2.1 The number of samples and specimens required toobtain a specific level of statistically valid results may bedetermined using Test Method E122. However, it may not beeconomically practicable to achieve specific confidence levelsand professional judgment may be required.
38、7.3 Specimen MachiningSpecimens shall be machined insuch a manner that the machining process does not affect thespecific heat properties of the material. Any fluids used in theprocess shall be compatible with the specimen and removedfrom the specimen prior to tests.7.4 The specimen shall dry to cons
39、tant mass in accordancewith Method D618, Procedure B, prior to testing.8. System Calibration8.1 Calorimeter Fluid CalibrationPerform a total of 15drops in order to calibrate the receiver fluid. Specifically, dropeach of the three calibration specimens from five temperaturesthat are approximately eve
40、nly spaced from 373 to 573 K. Theprocedures described in Section 9 should be followed toperform to perform these calibration drops.8.2 Calculation of the Heat Capacity of the ReceiverAfterthe 15 drops have been performed according to the proceduresdescribed in Section 9, calculate the mcpof the rece
41、iver foreach drop (see 3.3). Plot the results as a function of droptemperature. The results (at each drop temperature) shall bewithin 61.5 %. Plot a straight line through the averaged resultsat each temperature. This is the calibration curve to be used indata reduction. To allow for minor loss in ca
42、libration fluid, themcpcan be adjusted each time for mass loss. Maximum totalmass loss shall be less than 5 %.8.3 System VerificationEvery 10 drops or every 24 h,check the calibration of the receiver by dropping one capsulefrom 473 K. The result must be within 61.5 % of thecalibration curve determin
43、ed in 8.2. If this is not the case, thenthe receiver fluid must be recalibrated or changed and the newfluid calibrated.8.4 Capsule CalibrationThe empty capsule shall be cali-brated by testing it in accordance with the testing proceduredescribed in Section 9. A minimum of five drops at differenttempe
44、ratures that are approximately spaced evenly from 373 to573 K is required to calibrate the capsule. The capsule shall berecalibrated every time a change is made (for example,replacing the gasket), and its calibration shall be verified witha single drop, with a frequency of at least once a week durin
45、gperiods that the calorimeter is in regular use.9. Procedure9.1 Dry the specimen to a constant mass in accordance withMethod D618, Procedure B. Record the mass to an accuracy of60.1 %.9.2 Measure the mass of the calorimeter fluid in the receiver(Note 7) to 0.1 %, and cover the vacuum flask.9.3 Insta
46、ll the specimen in the capsule and seal the capsule.Suspend the sealed capsule in the heating system and monitorthe temperature of the specimen. Record specimen temperatureat least once every five minutes until thermal equilibrium isachieved (Note 8). It shall be assumed that thermal equilibriumis a
47、chieved when the specimen temperature is within 0.5 % ofthe furnace temperature and the specimen temperature does notchange by more than 0.02 K/min over a 10-min period.9.4 During the entire time that the specimen temperature isequilibrating in the furnace, the temperature of the receivershall be mo
48、nitored and recorded to 0.0025 K at least onceevery 5 min. If there is a drift in the receiver temperature, itshall be constant and less than 0.05 K/min.9.5 After the specimen has reached thermal equilibrium,position the furnace over the vacuum flask (Note 9). Momen-tarily remove the cover from the
49、vacuum flask and drop thespecimen into the calorimeter fluid. Replace the cover imme-diately after the drop. If during the drop, the specimen hitsanything prior to reaching the calorimeter fluid, the drop shallbe disregarded and repeated.9.6 Continuously monitor the temperature of the calorimeterfluid after the drop until the temperature drift is less than orequal to the drift just prior to the drop.NOTE 7A common method for measuring the mass of the fluid is toD4611 163measure the total mass of the vacuum flask and fluid and mass
